IF NOT EXISTS
(
	SELECT *
	FROM dbo.[syscolumns]
	WHERE [id] = OBJECT_ID(N'dbo.[ExampleTable]') AND [name]=N'ColumnName'
)
	BEGIN
	ALTER TABLE dbo.[ExampleTable] ADD [ColumnName] int NULL
	ALTER TABLE dbo.[ExampleTable] ALTER COLUMN [ColumnName] int NOT NULL
	END
GO